Fuel low level warning light

[cruiser]

Would I be correct in assuming that power is permanently applied to the fuel low level warning light and that it illuminates only when the tank float switch closes and applies an earth to the circuit?

My reason for asking is that I have a fault with the lamp - it's intermittent, but on most of the time (with plenty of fuel in the tank). When I disconnect the 3-way connector on the right side of the tank the light goes out, which indicates to me that - if my assumptions above are correct - the fault could not be caused by a short anywhere between the lamp itself and the aforementioned connector (caused, for example, by tightly routed handlebar cables). I don't have a wiring diagram to check the circuit.

[sweatmark]

From the BWM Motorrad "Electrical Circuit Diagrams" cd-rom, P/N 06 73 7 713 999, for model years 1993 to 2007. Cost too many dollars, but worth every penny.

• All warning lamps are powereddirectly +12vdc through Fuse 1;
  The various indicator fault switches/circuits control ground for the lamps;
  Fuel warning lamp H9220 ground routes through indicator connector X9003, to indicator damping control unit A9229, to fuel pump assembly M9100.
  Damping control unit is supplied by Fuse 1, and with ground to battery.

So, problem could be: (1) level switch in fuel pump assembly, or (2) indicator damping control unit?

[boxermania]

cruiser

You are correct on both statements. Yes, the connection to activate the light is to ground and if you disconnet the plug on the right side of the tank and the light goes off the problem is from the plug to the float in the tank.

Other tthan shorts on the wire, two things come to mind, one if you have removed the pump for service and in the process and inadvertedly the float arm was bent to where is not allowed to float with the gas or if something has gone wrong with the float. In either case removal of the tank is a must.....hope it is close to empty, if not run it down.

Good luck..................

[FloridaNative]

The float is housed inside a plastic enclosure. Don't think you could casually damage it.

[pebmr]

Cruiser:

Were you able to fix your warning light problem? My 04 just started doing the same thing two tankfulls ago. On most of the time, sometimes off, even when full. It's starting to bother me now. Have not looked into it yet but I will be taking the tank off to replace the battery. I was prepared for the QD thing, but now I may need to do something with this light/float?

[rdsmith3]

I had an intermittent problem with the low fuel indicator two years ago. A dealer looked at it and could find nothing wrong.

After a month or so, it went away. I have never had the problem again. Weird.

[oiasghar]

I had the same problem on the used R1150R I got. It was at first intermittent and then the light would just stay on. I pulled the fuel flange out and played with it a bit by turning it upside down and right side up to see if the light worked (make sure you disconnect the fuel pump before turning they key on) It worked at times but some sometime I had to fiddle with it with a screwdriver. I ended up getting a used fuel flange with float (no fuel pump) from Beemerboneyard.com and transferred my fuel pump over. Problem solved but not sure what was the exact cause other than the float stopped working. May be corrosion in the internal mechanism of the float.

[BigTaste]

Hello,
I have the same problem with my 12'2004 R1150R.

The BMW work shop disassembled the fuel pump unit shaked it up and down until the floater began to move.
But after leaving the work shop the malfunction was still present.

I am sure there mus be dirt like rust,sand or maybe particles form the coating of the fuel reservoir which entered through
the small hole into the floater housing and is now blocking the floater.

What do you think about ultrasonic cleaning?
Or maybe carefully break open the housing, cleaning and then glueing with fuel resistent glue?

BR
BigTaste

[boxermania]

Friends....one thing that has not been looked into......the dreaded nylon ties on the bundles of cables coming to the instruments.

Tight nylon ties from the factory and movement of the hanldebars over time flexes the wires and eventually they break, causing all these maladies. There was a recent post, again, on the subject.